1971	5.9	4.4
1972	5.6	3.2
1973	4.9	6.2
1974	5.6	11.0
1975	8.5	9.1
1976	7.7	5.8
1977	7.1	6.5
1978	6.1	7.6
1979	5.8	11.3
1980	7.1	13.5
1981	7.6	10.3
1982	9.7	6.2
1983	9.6	3.2
1984	7.5	4.3
1985	7.2	3.6
1986	7.0	1.9
1987	6.2	3.6
1988	5.5	4.1
1989	5.3	4.8
1990	5.6	5.4
1991	6.8	4.2
1992	7.5	3.0
1993	6.9	3.0
1994	6.1	2.6
1995	5.6	2.8
1996	5.4	3.0
1997	4.3	2.3
1998	4.5	1.6
1999	4.2	2.2
2000	4.0	3.4